Yankee drier



Nov. 20, 1 1 H. M. OSTERTAG ET AL YANKEE DRIER Original Fi1ed Sept. 21,1944 3 SheetsSheet l H. M. OSTERTAG ET AL Nov. 20, 1951 YANKEE DRIER 3Sheecs-Sheet 2 Original Filed Sept. 21, 1944 Nov. 20, 1 1 H. M. OSTERTAGET AL YANKEE DRIER 3 Sheets-Sheet 3 Original Filed Sept. 21, 1944Patented Nov. 20, 1951 YANKEE DRIER Harry M. Ostertag, Drexel Bill, andJohn B. Masshard, Chester, Pa., assignors to Scott Paper Company,Chester, Pa., a corporation ci Pennsylvania Original applicationSeptember 21, 1944, Serial No. 555,146. Divided and this applicationNovember 30, 1945, Serial No. 631,886

11 Claims. 1

. A primary object of this invention is to provide a Yankee driercapable of operating safely at steam pressures materially in excess ofthese heretofore found practicable.

To this prmary end the invention contemplates a novel structural designcalculated to eliminate the critical points of failure and to avoid inlarge part the hazards existing in driers of conventional form andresponsible for the inability of those driers to operate With reasonablesafety at higher steam pressures.

Another and more specific object of the invention is to provide improvedand readily accessible meansfor distribution of steam within the drierand for removal of condensate.

The invention resides further in certain structural details and deviseshereinafter described and illustrated in the attached drawings where-Fig. 1 is a longitudinal sectional view of a drier made in accordanceWith the invention, said section being taken on the line ll of Fig. 2;

Fig. 2 is a sectional view on the line 22, Fig. 1;

Fig. 3 is an enlarged fragmentary sectional view illustrating certaindetails of structure;-

Fig. 4 is a view in perspective of one of the elements of the structure;

Fig. 5 is a sectional view on the line 55, Fig. 1, and

Fig. 6 is a line diagram;illustrating graphically the inter-relation ofcertain elements of the structure, as hereinafter more fully set forth.

The conventional Yankee drier consists of a cylindrioal cast iron shellmounted on journals through the medium of dished heads, said shell andheads forming together a cylindrioal drum. Steam is introduced throughthe journals to the interior of the cylinder subjecting the entireinternal area to full steam pressure. Condensate is removed by scoopswhich operate either as dippers or, in the blow-through type of removal,as intake nozzles.

This type of construction possesses certain un desirablecharacteristics. (1) The pressure acting on the heads produces stressesand deflections of the heads which are transmitted through the rim boltsor studs to the shell; (2) Accumu lation of condensate may occur in thelarge insmall number of relatively spaced scoops tends to result in thecreation of local hot spots in the shell where the exhaust steam sweepsthe drier surface, With resultant uneven drying of the paper; (5) Thereare points of critical weakness. While some failures of Yankee driershave occurred in the head, the majority are in the outer shell, andthese latter failures almost invariably occur at the edges of the shelland usuallyat a rim boit or stud.

All of the foregoing factors have contributed to a necessity foremploying relatively low steam pressures. As previously set forth, thepresent invention provides a drier structure which, by eliminating theaforedescribed hazards and areas of critical weakness, permits the safeuse of materially higher steam pressures within the drier than haveheretofore been found practical. The invention also corrects insubstantial degree the several faults above enumerated of the priorconventional type of drier.

With reference to the drawings, the improved drier consists of an outercylindrioal shell I of cast iron, which metal provides the best crepingsurface, and an inner shell 2 which is made of steel so as to meet thestandard specifications for unfired pressure vessels. These shells arespaced apart through the medium of hollow rims 3 and 4, one at each end,which serve also as annular steam chambers. The rims and shells areconcentrically mounted, through the medium of spokes 5, upon a centralaxle 6, said axle comprising journal elements 1 and 8, from which thesaid spokes radiate, and an intermediate hollow shait 9 which extendsbetween and unites the said journals. Steam is introduced through thejournal 1 by way of a pipe 1 l which is secured to the outer end of thejournal through the medium of a fiange [2 and screws l3, as hereinaftermore specifically described. From the journal member l, steam passesthrough a port I4 to the hollow shaft 9, thence through the spokes 5 atboth ends of the structure to the rims 3 and 4, and from these hollowrims through apertures l5 and l6 to the space I 1 between the shells Iand 2. As shown in Fig. 2, the apertures l5 are uniformly spaced inannular series around the inner side of the rim 3, and the apertures 16are correspondingly arranged in the rim 4.

To remove condensate and reduce the thickness of water film on theshell, exhaust steam is evacuated frcm the chamber Il by way of aplurality of nozzles l8. These nozzles project from pipes l9, aplurality of which extend longitudinally in the interior of the steamchamber H and are connected at one end through pipes 21 and 22 and ports20 With the interior of the journal 8. Exhaust steam discharges throughthe journal and through a pipe 23 secured within the latter. The nozzlesI3 have their outer ends l8by arranged in close proximity to the innersurface of the outer shel1 l 50 as to restrict the openings throughwhich the steam must pass in entering the nozzles, and preferably theouter ends of the nozzles are formed, as shown in Fig. 4;, with lugs[30L which preclude approach of the ends of the nozzle to the innersurface ofthe s'hell'to an extent reducing said openings beyond apredeter mined minimum. By reason citheserestfictions;

the steam enters the nozzles at high velocity and sweeps the water fromarea2s of the inner surface of the outer shell adjacent to the nozzle;tips. Since the exhaust steam can enter the n'ozales from alldirections approximately in the plane of the drier surface the aforesaidsweeping action is effective over a circular area surrounding eachnozzle. The nozzles are closely spaced so that the combined area thussweptmay in aggregate cover substantiaily the entire inner surface ofthe shell. The exhaustingsteam carries with it the condensate which isSimilarly exhausted through the journal 3 and pipe 23 as described.

Opposite the outer end of each *of the spokes 5 is a tie rod.'24. 'Theserods are secured under of the boss 4l. Suitable packing 44 is insertedbetween the said outer end of the boss 4l and the bottom of the.recessin the cap 36' so as to seal the opening 43. A corresponding connection,sec

Fig. 1, is estabiished between the pipe l9 and the rim 3 with theexception that in this case the L fitting 39 is replaced by a terminalcap 45 which fits into the packing recess on the inner side of the cap33 and into which the screw 42 is threaded as described. By tighteningthe screws 42 at the opposite ends of the pipe I!) the latter is placedunder tension between the rims 3 and 4.

In the present instance the fittings 45 are pro vided .Withprojectingbosses 45 which can be utilized in applying or rem0ving the terminal cap.to the pipe [9.

Since the pressure component carried by the tie rods'and pipes isreiatively small, it may be desirable in some instances to eliminate thetie rods and to remove the tensile stress from the pipes. In such eventthe pressure forces may be carried by one of the shells and the rigiditycf the head structure.

tension, by means of nuts 25 and 26 at the re g): spective ends thereof,in the outer walls of the and 4, which apertures correspond to the aper-7 opening around the pipe "2|. The rim 3 is simituresl5 and 15previously described. These rods, in conjunction with the pipes l9, actunder tension to carry the relatively small component of the pressure ofthe steam in the chamber I! The outer which tends topseparate the rims.shell 1 is stifened by inwardly projectng intethrough outwardlyextending Ilanges 32 on the said rims and through :the fianges 29 andare -threaded into a segmentedretaining ring 33, the

segments of said ring seating against the inner faces of the fianges 29as best illustrated in Fig. 3.

The manner in whichthe nozzle pipes or'manifolds l.9 may be securedunder tension in the rims 3 and 4., isbest shownin Fig. 3. The outerwalls .of the rims are provided with a series of uniformly spacedelongated apertures 34which are located respectivciy approximatelymid-way between the points wherethespokes join the rim. The location andarrangement of these apertures 34 is well illustrated in Fig. 2. Theapertures are dimensioned and positioned *so that the respective pipesi'3 With their n0zzles may *be inserted therethrough into the chamber H,and for this purpose corresponding apertures 35 are provided in theinner Walls of :the said rims. The apertures 34 are norma;ily closed bycover cle- As shown most clearly in Fig. 3 the outer ends of the pipes2l are threaded into the respective fittings 39, and the innerperipherai wall of the rim 4 is provided with a series -of apertures forpassage of the said pipes 2i into the interior of the rim. Each of theseopening's;which are designated in Figure 3 by the referencenumeral 41,is provided with a stufing box indicated generally by the referencenumeral 48 which seais the larly provided with series of openingscorresponding to the opehings 41 and to the ports 2!) which receive thepipes 22, said openings and ports being desighated by the same referencenumerals, but in the rim 3 these openings are normally closed by meansof suitable caps 49 and screwed to the rim.

In accordance with the present invention, the inner shell 2 is mountedon the rims 3 and 4 through the mediu'm of fioating joints designatedgenerally by the reference numeral 51. One part of the joint is formedby a fiangelike annular projection 52 having its outer face 35 inclinedto the axis of the roll. The other part ofthe joint is'formed by aninturned flarige 54 at*the end of the inner shell 2, the inner faces 55of the fianges 54 being inclined in conormity With the face 53 of theflange 52 and seating upon the latter. The joint between the faces 53and 55 is sealedby a flexible sealing ring 56 which is secured at theinner end of the joint with its inner and outer peripheral edges securedby screws 51 and 58 to the flanges 52 and 54 respectively.

This sealbeing flexible is a character to afiord limited relativemovement between the rims and monts 33 which are secured against theouter Walls -of the rims .by screws .31, and each of the caps 3(ihas onits inner face a ;projecting annular wal1 '38 which forms a .recess onthe inside of the cap functioning for a purpose hercinafter -described.1Each of the pipes 19 has at the inner shell. 7

The locus of a point on the end of the inner she1l moving as a result-of thermal expansion is a line theyslope of which is determined bytherelation of'the diameter of the shell to its length. Byproperdetermination of this locus, it *is pos' sible to design the joint 51 sothat expansion of the shell and rims wili not open the joint i. e.

.. so that the surfaces 53 and 55 will remain in one end an L fitting 39which is attached by .threads to the pipe outer end a .projecting boss4l which fits into the aforesaid .recess embraced bythewafll 33 on the19 and which has at its associated cap 36 as previously set fort-h. A

, screw 42 passes through an aperture 43 in the cap 35 and through theaforesaid recess and is threaded .into a tapped hole in the outer facerate of heating and resultant expansion; and that the entire structurewith the exception of the outer shell is subjected to substantiafly fullsteam pressure and temperature. The outer shell, while subjected to fullsteam pressure will be cooled by the application of the wet web.

The axial expansion of the steei inner shell may be expressed asfollows:

a=L C(T2-T) where e:.=axial expansion L=length of shell C=coeificient ofexpansion for stee1 T=room temperature, and

Tz=operating temperature. The radial expansion of the shell will be:

Cr=RXC(TQT) where R=radius of the shell.

It may be assumed that one-hait of the axial expansion will occur ateach end of the shell. The

said slope will, therefore, be the ratio of the expansion or where aisthe angle of the locus, neglecting radial deflection due to pressure,and D is the mean diameter of the shell. The equation is iilustratedgeometrically in Fig. 6 wherein alpha corresponds to the angle formedbetween the surfaces 53, 55

(as shown in Fig. 3) and the rotary axis of the drier.

The central journal 1, the hollow shaft 9, the

spokes 5, and the rims 3 and 4 may be practically considered as aunitary structure since ail are straining the expansion and withconsequent The flexible seal 56 will avoidance of stresses. prevent theescape of any small quantity of steam which might find its way throughthe joint.

With further reference to the pipes I9, it will be noted that by reasonof the fact that all connections are external or readily accessible, the

pipes may be installed and as readily rcmoved without affecting the restof the structure. In the assembly operation, the nozzles, pipe, terminalfitting 45, and L 39 may be assembled and then inserted between theshell through one cf the cpenings 34. This sub-assembly after insertionis rotated through an angle 01 90 to the final position and the packingand coverplates installed and secured. The pipe 2| is then insertedthrough the aperture 41 and threaded into the L after which the packingis inserted and the gland drawn tight. Finally the S pipe 22 isinstalled between the nipple and the hub casting and is bolted fast tocomplete the connection. Dismantling may be quickly accomplished byreversing this procedure and may be accomplished without waiting for thedrier to cool.

The aforedescribed' drier structure has certain advantageous featureswhich may be summarized as follows:

1. Distortion at the ends of the heated outer shell is resisted by astiffening ring or flange through which the shell is fastened to a heavyrim section in a manner approaching an integral structure.

2. The bolt arrangement is such that the stresses therein are limitedsubstantially to those 01 drawing up, all the load being carrieddirectly by the rim section.

3. Forces due to weight or external load are transmitted to the journalsthrough the spokes radially in a plane perpendicular to the axis andclose to the bearing support, thereby reducing bending moments to aminimum. 4 i. Both end pressure and water load are re duced to apractical minimum by employing a double shell. This reduces stress anddeflection in the heads and shell and also reduces the hazard of largevolumes of escaping steam should failure occur.

5. Tie rods and the pipes 19 may be used to carry end pressure forcesrather than utilizing the outershell and heads thereby further reducingstresses and defiections in the heads and shell.

6. Provision has been made to equalize expansion where possible and toprovide an expanding joint between dissimilar metals whereby variatiensin expansion will not produce undue stresses.

7. Steam is introduced between the shells from a large number ofapertures to provide uniform distribution and does not impinge on theouter shell, which avoids creation of hot spots.

8. The condensate-removal nozzles are designed and located to produceexhaust steam velocities suficient to sweep a circular area about eachnozzle. A number of nozzles are provided so that the area swept by eachmay overlap the area swept by an adjoining nozzle thus sweepingsubstantielly the entire shell surface to reduce the water filmthickness and increase heat transfer.

9. The condensate removal system has been designed for accessibility andeasy removal to reduce operating delays when maintenance is required.

Reference is hereby made to U. S. application Serial No. 555,146 filedSept. 21, 1944 now Patent No. 2,563,692 of which this application is adivision.

We claim:

1. A drier of the rotary cylinder type comprising a cylindrical shellforming the peripheral surface of the drier, means for admittingpressursteam to the interior of the shell, and exhaust conduit means forsaid steam including a mul tiplCity of exhaust ports distributed oversubstantially the entire inner surface of said shell, said ports beingdirectd radially toward and in immdiate proximity to the inner surfaceof said shell so that the steam in passing to said ports will flow athigh velocity over and in contact with said surface.

2. A drier, in accordance with claim 1 wherein the said discharee portsare defined by open ended nozzles which project radially from saidconduit means into close proximity to the inner surface of said shell.

3. A drier of the rotary cylinder type comprising a cylindrical shellforming the peripheral surface of the drier, end walls for said shell,means for admitting steam to the interior of said shell, a plurality ofpipes mounted in said shell and having each a plurality of nozzles, saidnozzle and pipes being distributed in substantiallly uni- Iormp;territhitoughout the interiorof said s11e11 and ,eonstitutingzmeans forexhaust f steam and 'aondensate from the latter, and said -nozz1es pro-,iee1ng toward'the inner surface of said she1l-with their intakeopenings directed radially toward and in 1oso'proximity to the innersurface of said sha11 whereby the steam diseharged into said opfiflingsWil1 sWeep a substantial -area.of the said inner surface aroundeachofthe nozzles to thereby-zeffiectively reduce the water film on saidsurface. 7

' inca drier of the rotary cy1inder type, 1 an enter cy1indriea1 shell,;an -inner she11 Iadia1lY spaced from the outer .shell 50 as :to providetherebgtwen 'a steam chamber, end wal1s for said ehamberc, :means foradmitting steam to said chamber; and exhaust conduit means extendinginto said chamber through a wall thereof and having a multiplieity o,fports distributed throughout the chamber for discharge of steam andeondensate from the latter, said ports being diree*fied radiallytoward-and in immediate proximiyto the :inner surface .of :the outershe1l.

" 5, A drier aoeordance with claim 4wherein means is provided foradmitting steam SII1? taneomly to :both ;ends of said chamber.

' 26. -A drier inaccordance with claim 4 wherein the,said disehargeportsare defined byepen ended nozzles which project radially from saidconduit meang into close proximity to the inner surface of :the outershell. r

=r.'In a ldrier of the rotary cy1inder type, an enter pylindricalshell,an inner coaxial shel1 supporting usaid she1ls fzor rotation about ;the

.common axis, said.means including a holiow J3}I" nu1ar rimmember .at;each endzof the sh11s oonnecting the 1atter,x-means operativelyassoeiated:with-:said rims for admitting steam to said in each of saidpipes,.,a -p1ura1ity of ports in the radially spa ced from the outershell 50 as to proide"therebetween a chamber for reception et steam,means for admitting steam to said chamber,.a pluraiity ofpipes mountedin said chamber aridhaving each a pluralit of nozzles, said nozz1es andpipes :being distributed in substantially unifrmpatternthroughout thechamber and constituting means for exhaust of steam and condensate iromthe latter, and said nozzles projecting toward the outer shell withtheir intake openjngs directed radia1ly toward and in close proxmity tothe inner surface of the shell whereby the steam discharged into saidopenings W111 swep 'a;substantial area of the said inner surface aroundeach of the nozz1es to thereby effectivel reduce the water 'fi1m on saidsurface.

8. In a drier of the rotary cylinder type, an outer cylindri al shell,an inner co-axia} shell radiallyspaced from the outer. she1l so as toprovide therebetweefla steam chamber, hol1ow an nular rim members at theends of said chamber, said rim menibers eonnecting the shlls and havingports opening to said chamber, a pair of hol- 1oxv journal elements andho11ow spokes connecti-ng said journal e1ements with the respective rimmembers thereby to afiord' passage for steam to said chamber, a seriesof pipes each supported in said rim membersand extending -axiallythrough said chamber, said pipes being distributed in substantialuniformity about the circumference of the hamber and *each carrying ap1urafity of -nza1es 'pmjecting -outwardly with their open fendsdireeted :radiauy toward and in close prox. imit to'the inner surfae oithe said outer shell, and a duct extending from each of said pipes toone or said holiow journals for disoharge -through th flatter of steamand condensate from the said Vi.d a:steam -chamber .tne eb twe n. m ans.to.r

outer side of at least one of said rim members, said ports being inalignment With said pipesand providing for insertion of the pipes and-nozzleg through the rim and into said chamber, ,means operativefrom,thetoutside .of said rims fer detachably secu1*ing the pipes in therime, and .a detachab1e cover plate}forsaid ports.

10. In a drier of the rotary cylinder type, an outer c'ylindricil shell,an irlner co-axia1 s11e11 radially spaced f romvthe,outer shell so as toprovide therebetween a chamber for reception ,of steam, means foradmitting stam to said chamb er,;a p:1ura1ity of pipes ;mounted in saidchamber; said,pipes having open, ended nozz1es proieetinginto*-c1oseproximity to and with the terminal ports confronting theinner surface o f said outer shell, said nozz1es and pipes constitutingmean s fgr exhaust of steam,and pondensate from the chamber, and meansfor :positive1y 1imiting the s paoing of the nozzle tips from the saidinner Surface to a predgtermined minimum.

11 In ,a drier of the rotary .oylinder type, an enter cy1indrica1 shell,an inner coaxial shell radiauy spaced fr om the.outer she1l so as toprovide therebetween asteam chamber, a rim member at each end of saidchamber uniting said shel1s, means for admitting steam ,to said cham-REFERENCES CITE!) Iheofloying references are of record in the -fi1 ofthi Patent: r

UN ITED STAIES PATENTS 'Number Name Date .;543,051 Phillips July ;23,1895 550,988 Mandot Dec. 10, 1895 -1,196,440 Doy 1e Aug. ,29, 19161,521,223 Wyld Dee.30, 1924 1,741,101 Dinardo eta1. ---Dec. 24, 19292,104,558. Gu%nheim Jan.A, 19.38 2,420,824 ,Hornbostel. et al. May 20,1947 7 4 FOREIGN PATENTS Number Country Date 1,253 Great Britain Mar. 8,1883 of 1883 r r 17,564 Great Britain Aug. 21, 1908 --of1908 r 195,975A, Germany Oct. 13, 1906 618,742

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